In scrap collection yards where large quantities of pieces of metal scrap material are temporarily stored, mobile cranes are utilized for lifting and moving scrap pieces from one location to another. Such cranes can consist of a large tractor or vehicle upon which a boom is mounted, with the boom terminating in an electromagnetic device for attracting and picking up ferrous metal pieces. The tractor-like vehicles may be driven about the yard to pick up and deliver pieces of scrap material from one location to another. Because electromagnetic devices require an electrical power source, a power delivery cable can be attached to the vehicle at one end and have an opposite end connected to an electrical power terminal to which electricity is delivered from a power supply company or the like.
In the environment of a scrap yard, where there may be piles of debris or piles of scrap material, the crane must be driven carefully around and about the yard. Thus, the power supply cable must be similarly moveable in response to the location of the crane. However, where the cable is simply attached at one end to the power source and moved upon the ground to the crane vehicle, there is a danger of the vehicle running over the cable or tangling the cable in other piles of scrap or debris around which the vehicle moves.
Thus, in that kind of environment, and in similar types of environments where electromagnetic cranes and the like are used and power supply cables are needed to supply the electricity for the equipment, it is desirable to keep the cable well above the ground and at the same time form the cable in such a manner that it self-adjusts its direction of extension and its height above the ground, as well as keeping it taut and generally horizontal in response to the varying locations of the crane carrying vehicle. Thus, it would be desirable to have a self-adjusting mechanism or equipment which automatically, without manual intervention, consistently maintains the cable taut, well above the ground, generally straight and approximately horizontal above debris and other piles, and directed in a straight line from the power source to the vehicle no matter where the vehicle wanders about the location. The invention herein is concerned with providing such automatic self-adjusting cable equipment.